Mark,
In the UK I am insured to drive my vehicle. My insurance premium depends on which vehicle I drive, how long I have held a full driving license, driving convictions if any, and number of years no claim bonus if any.
As my insurance is fully comprehensive, I am insured to drive a car belonging to someone else but not hired, on a third party basis. Another qualified driver is allowed to drive my vehicle, again on a third party basis.
For an extra premium another regular driver can be named on the policy to have fully comprehensive cover.
It is as simple as a question of whether in the UK, is it the driver or the car that is insured because it is a combination of both.
I remember when I was in the army and based in Germany (where I learnt to drive) it was the car that was insured, not the driver.
There was an increase in premium for younger drivers, however if the car was stolen and crashed or injured another driver or pedestrian, they could claim on the insurance as the car was insured.
In the UK this is not possible as the usual driver or one qualified and driving with his/her permission was not driving.
Dave.